Once called “ASP”, but now called “Classic ASP”, because it’s been replaced by ASP.NET, is Microsoft’s first implementation of a technology to let developers create web applications with code that runs on the server to provide actual functionality, as opposed to just static HTML that has no functionality.
Microsoft provided 2 languages that could be used on the server side:
- VBScript
- JScript
VBScript was a variant of Visual BASIC and was not object oriented at all. JScript was a much better language, but almost no one used it.
To create a web page using classic ASP technology, a developer would write the HTML, then would embed snippets of VBScript code throughout the HTML. Additionally, if the VBScript needed to read or write to a database, the programmer would also embed SQL (a database language) snippets throughout the file. And, if the developer wanted any client side functionality (like changing focus on a text box or validating data before posting, for example), he would also embed JavaScript throughout the file.
This make one, gigantic, huge, ugly mess of 4 languages intermixed in ONE source file. On top of that, variables were untyped, leading to programming errors, and the code was interpreted at run time, instead of compiled, reducing performance.
Fortunately, that technology was superseded in February of 2002 with the full release of v1.0 of the .NET Framework.
Now, with ASP.NET, the server side code is in its own source file, is written in either C# or VB.NET (both fully object oriented languages), and the only thing in the HTML file is HTML and JavaScript. The server side code is compiled (so it’s fast), and all variables are fully typed, leading to fewer errors and many errors being caught by the compiler before the application is even run. A full debugger is also provided.